Development history of waste circuit board electronic parts disassembly equipment

PCB circuit board, also known as printed circuit board, is the provider of electrical connections for electronic components, the substrate for assembling electronic parts, and a printed board that forms point-to-point connections and printed components on a common substrate according to a predetermined design. It has a history of more than 100 years of development, and its design is mainly layout design; the main advantage of using circuit boards is that it can greatly reduce wiring and assembly errors, improve the level of automation and production labor rate, and can be divided into single-sided, double-sided, four-layer, six-layer and other multi-layer circuit boards according to the number of layers of the circuit board. The PCB industry belongs to the basic industry of the electronic information product manufacturing industry. By seizing the opportunity of a new round of development of the global electronic information industry, focusing on the core of industrial structure adjustment, it vigorously promotes independent innovation and realizes the stable and sustainable development and transformation and upgrading of my country's printed circuit industry. It realizes the upgrading of industrial product structure and technology, forms competitive large-scale production capacity in advanced products and fields; forms high-end materials, equipment, instruments and service industry supporting through independent innovation; produces a circular economy, and realizes the development of the printed circuit industry towards a low-carbon industry. Therefore, the use of printed circuit boards plays a vital role.

But on the other hand, with the rapid development of science and technology, the number of discarded electronic and electrical products is increasing. Circuit boards are the main body of electronic and electrical products, and are also the difficulty in recycling discarded electronic and electrical products. They have the characteristics of high chemical value and high recycling difficulty. Therefore, the recycling of discarded circuit boards has received attention from many research institutions at home and abroad. Foreign circuit board recycling pays more attention to the reuse of electronic components and extends the service life of electronic components as much as possible to reduce the material demand for the production of new components and the waste emissions generated in the production process, so as to save resources and energy. my country's research on the recycling of circuit boards started late, and most of the research was limited to the recycling of circuit board substrates, that is, the processing of circuit boards. There is less research on fine processing methods such as circuit board electronic component removal technology. The recycling method adopted is to directly crush the raw materials and recycle them as a whole, which is a serious waste of resources and has a great impact on the environment. Based on the analysis and comparison of the existing circuit board electronic component removal technologies at home and abroad, a more perfect removal process is proposed in view of the differences in welding process, removal force and recovery value of circuit board electronic components, such as: Circuit board disassembly equipment (burning board machine): Old home appliance circuit boards, circuit boards, and defective products contain various electronic components such as capacitors, relays, and transformers, which need to be thermally detinned before the next step. The purpose of thermal detinning is to separate the electronic components and solder of the waste circuit boards from the circuit boards. The circuit board first enters the drum with end holes through the feed port, and then is heated to a temperature of about 150°C by an electric heating device to loosen the tin on the circuit board. The drum rubs against the drum wall, and the friction separates the solder, electronic components, and circuit boards on the circuit board. The separated solder and electronic components slide down the channel to the multi-layer sorting screen, and the electronic components and solder are sorted out by the sorting screen. The sorted circuit board will enter the crusher through the conveyor for crushing. The tin collected during the hot detinning process is sold as a product; the waste gas generated is mainly dust and waste biogas. Solid waste mainly includes screened electronic components, water mist, and waste activated carbon.

Tin balance analysis after disassembling the circuit board: The tin content in the raw material is 3.0%, about 5400t/a. After treatment, it is distributed in recycled tin, copper powder, resin powder and outflow dust, among which the tin content in recycled tin is 149t/a, the tin content in copper powder is 5020.2t/a, the tin content in resin powder is 230.78t/a, and the heavy tin content is 0.02t/a. At the same time, the circuit board disassembly equipment (burning board machine) realizes the functions of automatic loading, automatic disassembly, and automatic discharging. Later tests show that the equipment can disassemble the electronic components of the circuit board safely and reliably, and the damage rate of electronic components is low.